What ND filter

Shutterman

Shutterman

Suspended / Banned
Messages
6,508
Edit My Images
Yes
Hi there quick question, I have a cokin set of p filters and I want to add a ND filter to the set for the purpose of removing people from shots.

ie:- they will be there milling about and walking through the shot but will not show up.

However I do not know if this one will achieve that effect..

Cokin P154 Grey ND8X Filter

Assistance please....

Regards

Nigel
 
I'm not familiar with the Cokin range - however, an 8x should give you a reduction of 8-stops assuming their nomenclature is the same as everyone else's

So, if 100 ISO and f16 gives you 1/125 sec, then 8 stops less would be (1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1, 2 secs) a 2 second exposure

2 seconds isn't enough to 'remove' people, and even a 10x would still only be 8 seconds so some slow movers or static peeps will record

8x is enough on a 'duller' day though where f16/f22 starts you off closer to a 1 sec exposure

For a sunny day I reckon you'd need a 15x ND, and I'm not sure anyone makes such a beast !!!

HTH

Oh, and I find my 7x is adequate most of the time, though I use it for water shots mostly rather than people ones

DD
 
mmmmmm..you could always put 3no ND8's in the filter holder,and i'm sure that will give you a long enough exposure time to get the desired effect :lol:

i've only had that effect in darkness,like on westminster bridge at night..

plenty of people on here,but not visible with a 30 sec exposure...

DSC00334.jpg


or here on the millenium bridge...

DSC03409copy_filtered.jpg
 
DiddyDave said:
I'm not familiar with the Cokin range - however, an 8x should give you a reduction of 8-stops assuming their nomenclature is the same as everyone else's

So, if 100 ISO and f16 gives you 1/125 sec, then 8 stops less would be (1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1, 2 secs) a 2 second exposure

2 seconds isn't enough to 'remove' people, and even a 10x would still only be 8 seconds so some slow movers or static peeps will record

8x is enough on a 'duller' day though where f16/f22 starts you off closer to a 1 sec exposure

For a sunny day I reckon you'd need a 15x ND, and I'm not sure anyone makes such a beast !!!

HTH

Oh, and I find my 7x is adequate most of the time, though I use it for water shots mostly rather than people ones

DD
Click to expand...

great explanation dave...a cokin ND8 is a 3 stop filter,ND4 is a 2 stop and ND2 is a 1 stop..
 
Nope, an ND8 gives you a 3 stop reduction.
ND2 is 1 stop, ND4 is 2 stops, ND8 is 3 stops.

So, say for example, the correct exposure for something was 1/30 of a second, you'd reduce your exposure by 3 stops - 1/15, 1/7, 1/3
 
I tried this effect several years ago in daylight. can't remember the exact exposure but I had a ND0.9 plus a polariser to cut down the light, plus stopped down to around f22. Wasn't particularly successful.

Photoshop CS3 extended has a useful function, where by if you take a number of multiple exposures of the same subject ( min 4) it will subtract any pixel that doesn't apear in 50% of them . Bit expensive option though.
 
DiddyDave said:
ND8 is 3 stops? :cuckoo:

Don't you just love manufacturers for making things simple to relate to !!!

My BW is a 7x and it reduces the exposure by... wait for it... 7 stops

Good old Germans eh :thumbs:

DD
Click to expand...

Actually ND0.9 is 3 stops. These numbers refer to the density of the filter e.g a density of 0.3 gives a 1 stop change, 0.6 gives 2 stops. Personally I find this easier than 2x and 4x. But then every one to their own
 
Chappers said:
Actually ND0.9 is 3 stops. These numbers refer to the density of the filter e.g a density of 0.3 gives a 1 stop change, 0.6 gives 2 stops. Personally I find this easier than 2x and 4x. But then every one to their own
Click to expand...

Well I suppose that makes sense, but then stops are done in halves/doubles, so 2x being 1, 4x being 2, that makes more sense imo.

16x would be a 4 stop, with 64x being 6 stops...
 
Another each to their own point then

I don't want to even think about Maths when considering a shot, so if it looks like I need to stop-down 6 stops I'd much rather reach for a 6x filter than think about whether it's 32x, 64x or 128x

I used to play about with a rather old MF camera - a Kodak Junior #1 from 1908 - what made it potentially really easy for anyone was that the 3 f-stops it had were... 1, 2 & 3

Much easier for a novice to open up two stops than starting at f16 methinks

DD
 
Thanks for all the replies everyone.. I have decided on getting a couple of the ND8 and will try stacking the little devils.

There is a 100x filter out there for B&W I think but this is a screw in and I want the versatility of being able to use the filters on all my lenses.

Thanks for the answers...

Cheers

Nigel
 
You must log in or register to reply here.
Back
Top